OBJECTIVE:To prepare Baicalin proliposomes (PBA) containing sodium deoxycholate (SD) with optimized for-mulation,and to study pharmacokinetics of it in rats in vivo. METHODS:PBA were prepared by spray drying method. Response surface method based on Box-behnken design was adopted to optimize the formulation of PBA with the amount of HSPC,cholester-ol and SD as factors using entrapment efficiency of PBA as index. The particle size,morphology,leakage rate and stability of the optimal PBA were evaluated along with the pharmacokinetics of it(compared to raw materials)in rats after ig administration of 15 mg/kg. RESULTS:The optimal formulation of PBA was that the amounts of baicalin,HSPC,cholesterol and SD were 100,214, 68 and 53 mg,respectively;the predicted and practical values of entrapment efficiency were 86.42% and 84.32%,respectively, and particle size of the optimal PBA was 358.4 nm. The leakage rate of reconstituted liposomes was low and the stability of PBA was good. Compared with baicalin raw material,t1/2,tmax,MRT,cmax and AUC0-t of PBA were all increased significantly(P<0.05 or P<0.01 or P<0.001). CONCLUSIONS:PBA were prepared successfully using the spray drying method. This method is simple and easy,and the optimized formulation is feasible and can improve the oral bioavailability of baicalin.